What exactly was in that compound is unprovable. According to Ford’s project manager for the Soybean Car, it was “… soybean fiber in a phenolic resin with formaldehyde used in the impregnation.” Needless to say, Ford loved to demo his ‘plastic car’ by hitting it with an axe or a sledgehammer and showing no damage. Ford passed just a few years later, the formula vanished, the car itself was destroyed, and the tech never saw the light of day.